1. Field of the Invention
The present invention relates to a pin for use in fractured bones in arms or other parts of the body, to bring about support of the fractured bone while it is healing.
2. Description of the Related Art
It is generally known within the health care field that in the treatment of fractured bones means are used to allow reinforcement and support to the area surrounding a fracture in the bone in question.
Fractures of the distal forearm (wrist fractures) are the most common of all fractures (annual incidence about 3,000/1,000,000 inhabitants in the industrialized world) and constitutes by it's abundance a major therapeutic problem. Simple fractures are treated with just a bandage while more complex fractures often require open reduction and plate fixation. For a large number of the intermediate complex fractures the choice of treatment is less obvious; while plate fixation may be a too extensive and expensive procedure bandage immobilization may be insufficient to hold fracture fragments in the desired position while the fracture heals. Other therapeutic modalities also have their drawbacks: classic external fixation immobilizes the wrist joint during treatment and wrist stiffness may ensue. To avoid that, the external fixation is often removed before the fracture is consolidated, which may lead to secondary displacement of the fracture.
Another method is to use straight fine wires (1.5-2.0 mm in diameter) drilled into the fragments or introduced through the fracture site. While that is a simple and minimally invasive procedure it requires power tools. Also, the wires, being left protruding through the skin, have to be removed before the patient is able to mobilize her wrist.
The second bone of the forearm, the ulna, is notoriously difficult to fix, and fractures of the distal ulna are therefore often neglected. Pins have been used, among others, to hold together the bone fragments, or they have been inserted in the bone's inner canal. The pin has then either been allowed to remain in place after the fractured bone has healed, or it has been extracted afterwards. Plates similar to angle iron have also been used and are attached with screws to the bone by the fracture. Examples of such aids are shown in International Publication No. WO 01/56452 A2.
It has been difficult to operate in such supports by the fracture area, and even more difficult to remove them. Neither have those supports constituted an especially good pin in themselves, i.e., they have not interacted with the bone to achieve contact against the same during simultaneous tensioning of the pin. The introduction of the pin in the bone has not been facilitated with similarly known pins, and neither has the screwing of them into the bone been proven to be easy to achieve.
It is difficult to insert pins in the bone, and sometimes a power drill is required. It is also difficult to securely anchor the pin in the bone, which is why they frequently slide out. In addition, they are frequently left protruding from the skin, with the risk of both inflammation around the pin as well as infection, which can spread to the bone and develop into osteomyelitis.
An object of the present invention is thus primarily to produce a pin that is suitable for use in the healing of fractured bones in the arms or other parts of the body, and which solves, among others, the problems identified above, and which is also easy and cost effective to manufacture.